Bearing apparatus and spacer

Abstract

A bearing apparatus supports a rotating body with a bearing including an inner ring, an outer ring, and a rolling element. The bearing apparatus includes a power generator including a Peltier element variable in amount of power generation depending on a temperature difference between the inner ring and the outer ring caused in the bearing and an abnormality sensing apparatus that senses abnormality of the bearing based on the amount of power generation by the power generator. Preferably, the abnormality sensing apparatus senses abnormality of the bearing based on any of the amount of power generation by the power generator, a time derivative value of the amount of power generation, and following relation between the amount of power generation and another parameter. The bearing apparatus and a spacer in which abnormality of the bearing can accurately be sensed early are thus provided.

The invention claimed is: 
     
       1. A bearing apparatus that supports a rotating body with a bearing, the bearing including an inner ring, an outer ring, and a rolling element, the bearing apparatus comprising:
 a power generator including a Peltier element variable in amount of power generation depending on a temperature difference between the inner ring and the outer ring caused in the bearing; and 
 an abnormality sensing apparatus that senses abnormality of the bearing based on the amount of power generation by the power generator. 
 
     
     
       2. The bearing apparatus according to  claim 1 , wherein
 the abnormality sensing apparatus senses abnormality of the bearing based on at least one of the amount of power generation, a time derivative value of the amount of power generation, and following relation between the amount of power generation and another parameter. 
 
     
     
       3. The bearing apparatus according to  claim 1 , further comprising:
 a power storage apparatus in which electric power generated by the power generator is stored; 
 a load circuit that uses electric power in the power storage apparatus; and 
 a power supply that supplies a power supply voltage to the load circuit upon receiving a voltage of the power storage apparatus. 
 
     
     
       4. The bearing apparatus according to  claim 1 , further comprising a power storage apparatus in which electric power generated by the power generator is stored, wherein
 the abnormality sensing apparatus senses abnormality of the bearing based on a value resulting from time derivative of an amount of stored power in the power storage apparatus. 
 
     
     
       5. The bearing apparatus according to  claim 1 , further comprising a spacer arranged adjacently to the bearing, wherein
 the spacer includes
 an inner-ring spacer that abuts on the inner ring, and 
 an outer-ring spacer that abuts on the outer ring, and 
 
 the power generator is arranged in the outer-ring spacer. 
 
     
     
       6. The bearing apparatus according to  claim 1 , wherein
 the bearing apparatus is configured to support a rotation shaft of a machine tool. 
 
     
     
       7. A spacer arranged adjacently to a bearing that supports a rotating body, the bearing including an inner ring, an outer ring, and a rolling element, the spacer comprising:
 a power generator including a Peltier element variable in amount of power generation depending on a temperature difference between the inner ring and the outer ring caused in the bearing; and 
 an abnormality sensing apparatus that senses abnormality of the bearing based on the amount of power generation by the power generator. 
 
     
     
       8. The spacer according to  claim 7 , wherein the spacer includes:
 an inner-ring spacer that abuts on the inner ring; and 
 an outer-ring spacer that abuts on the outer ring, wherein 
 the power generator is arranged in the outer-ring spacer.